I would like to use the COPY function in PostgreSQL to import a CSV file into a PostgreSQL database.
Where it says the filename in the documentation, does the CSV file have to be stored in a specific location or can it be stored in any location.
For example, copy data_table from '/tmp/outputdata.csv' WITH DELIMITER AS ',' CSV QUOTE AS '"';. Where it says tmp, does that mean the tmp folder in the C: drive. Can it be change to another folder name?
It looks like you are confused by Linux vs. Windows file-path notation. What you have there is a Linux path anchored to root. Windows uses drive letters, which you can specify just as well when you are running on Windows.
If you use Windows notation, take care that you have to escape backslashes if you are not using standard_conforming_strings = on - which is the default in Postgres 9.1 or later, but not in older versions. Like:
COPY data_table from E'C:\\tmp\\outputdata.csv' WITH ...
With standard_conforming_strings = on you can simply write:
COPY data_table from 'C:\tmp\outputdata.csv' WITH ...
Note that a PostgreSQL Windows server also understands default path notation with slashes instead of backslashes.
For SQL COPY FROM / TO you can use any path that the owner of server process (postgres by default) has permission to read / write.
For the \copy meta command of the psql client the permissions of current local user apply.
Yes, of course you can specify whatever location where you have read access. There's no problem changing the path of the file.
Keep attention only on the fact that on windows you have to escape the backslash in this way :
copy data_table from 'c:\\Temp\\outputdata.csv' WITH DELIMITER AS ',' CSV QUOTE AS '"';
Related
lease=# COPY dhcpd_data (ip_address, start_time, end_time, mac_address, machine_name) FROM '~/outputcsvre.csv' DELIMITER ',' CSV HEADER;
ERROR: could not open file "~/outputcsvre.csv" for reading: No such file or directory
if i define the path as '/home/rihiraj12/outputcsvre.csv', it works fine.
Yes, that's normal.
You don't really have a directory called ~. When you execute a command on the command line, the shell will expand ~ to /home/rihiraj12 before running the program. But here you're not using the shell, so ~ is interpreted literally.
As a workaround you could say
COPY dhcpd_data (...) FROM PROGRAM 'cat ~/outputcsvre.csv' ...
But note that the COPY command is executed by the server, so this will make the server spawn a cat command and use the home directory of the PostgreSQL server.
To specify the file from your own point of view, you can (in psql) use the \copy meta-command (which has the same syntax as COPY):
\copy dhcpd_data (...) FROM PROGRAM 'cat ~/outputcsvre.csv' ...
This will use your own home directory as ~.
~ is a shortcut that unix-like shells can expand to be the home directory of your user.
i.e. if you use ~/outputcsvre.csv , the shell converts this to /home/rihiraj12/outputcsvre.csv before doing anything else with it.
Outside a shell, applications rarely implement this expansion - and neither does postgresql, so you have to provide real path to the file.
In the case of the COPY command in postgresql, it is executed by the server - so in this case you will have to provide a filename that the server can resolve and read directly. (i.e. a relative path would be relative to wherever the postgresql server is located - so use an absolute path for the file.)
I tried to make a variable in SQL statement in Postgresql, but it did not work.
There are many csv files stored under the path. I want to set path in Postgresql that can tell copy command where can find csv files.
SQL statement sample:
\set outpath '/home/clients/ats-dev/'
\COPY licenses (_id, name,number_seats ) FROM :outpath + 'licenses.csv' CSV HEADER DELIMITER ',';
\COPY uploaded_files (_id, added_date ) FROM :outpath + 'files.csv' CSV HEADER DELIMITER ',';
It did not work. I got error: no such files. The two files licneses.csv and files.csv are stored under /home/cilents/ats-dev on Ubuntu. I found some sultion that use "\set file 'license.csv'". It did not work for me becacuse I have many csv files. also I tried to use "from : outpath || 'licenses.csv'". it did not work ether. Appreciate for any helps.
Using 9.3.
It looks like psql does not support :variable substitution withinpsql backslash commands.
test=> \set somevar fred
test=> \copy z from :somevar
:somevar: No such file or directory
so you will need to do this via an external tool like the unix shell. e.g.
for f in *.sql; do
psql -c "\\copy $(basename $f) FROM '$f'"
done
You can try COPY command
\set outpath '\'/home/clients/ats-dev/'
COPY licenses (_id, name,number_seats ) FROM :outpath/licenses.csv' WITH CSV HEADER DELIMITER ',';
COPY uploaded_files (_id, added_date ) FROM :outpath/files.csv' WITH CSV HEADER DELIMITER ',';
Note: Files named in a COPY command are read or written directly by the server, not by the client application. Therefore, they must reside on or be accessible to the database server machine, not the client. They must be accessible to and readable or writable by the PostgreSQL user (the user ID the server runs as), not the client. Similarly, the command specified with PROGRAM is executed directly by the server, not by the client application, must be executable by the PostgreSQL user. COPY naming a file or command is only allowed to database superusers, since it allows reading or writing any file that the server has privileges to access.
Documentation: Postgresql 9.3 COPY
It may have been true when this was originally asked, that psql backslash commands didn't support variable interpolation, but in my PostgreSQL 14 instance that's no longer the case. However, the psql manpage is clear that \copy specifically does not support variable interpolation.
I'm trying to import a (rather large) .txt file into a table geonames in PostgreSQL 9.1. I'm in the /~ directory of my server, with a file named US.txt placed in that directory. I set the search_path variable to geochat, the name of the database I'm working in. I then enter this query:
COPY geonames
FROM 'US.txt',
DELIMITER E'\t',
NULL 'NULL');
I then receive this error:
ERROR: could not open file "US.txt" for reading: No such file or directory.
Do I have to type in \i US.txt or something similar first, or should it just get it from the present working directory?
Maybe a bit late, but hopefully useful:
Use \copy instead
https://wiki.postgresql.org/wiki/COPY
jvdw
A couple of misconceptions:
1.
I'm in the /~ directory of my server
There is no directory /~. It's either / (root directory) or ~ (home directory of current user). It's also irrelevant to the problem.
2.
I set the search_path variable to geochat, the name of the database I'm working in
The search_path has nothing to do with the name of the database. It's for schemas inside the current database. You probably need to reset this.
3.
You are required to use the absolute path for your file. As documented in the manual here:
filename
The absolute path name of the input or output file.
4.
DELIMITER: just noise.
The default is a tab character in text format
5.
NULL: It's rather uncommon to use the actual string 'NULL' for a NULL value. Are you sure?
The default is \N (backslash-N) in text format, and an unquoted empty string in CSV format.
My guess (after resetting search_path - or you schema-qualify the table name):
COPY geonames FROM '/path/to/file/US.txt';
The paths are relative to the PostgreSQL server, not the psql client.
Assuming you are running PostgreSQL 9.4, you can put US.txt in the directory /var/lib/postgresql/9.4/main/.
Another option is to pipe it in from stdin:
cat US.txt | psql -c "copy geonames from STDIN WITH (FORMAT csv);"
if you're running your COPY command from a script, you can have a step in the script that creates the COPY command with the correct absolute path.
MYPWD=$(pwd)
echo "COPY geonames FROM '$MYPWD/US.txt', DELIMITER E'\t';"
MYPWD=
you can then run this portion into a file and execute it
./step_to_create_COPY_with_abs_path.sh >COPY_abs_path.sql
psql -f COPY_abs_path.sql -d your_db_name
Using COPY statement of PostgreSQL, we can load data from a text file into data base's table as below:
COPY CME_ERROR_CODES FROM E'C:\\Program Files\\ERROR_CODES\\errcodes.txt' DELIMITER AS '~'
The above statement is run from a machine which has postgresql client where as the server is in another windows machine. Running the above statement is complaining me that ERROR: could not open file "C:\Program Files\ERROR_CODES\errcodes.txt" for reading: No such file or directory.
After some research, i observed that COPY statement is looking for the loader file(errcodes.txt) in the postgresql server's machine at the same path (C:\Program Files\ERROR_CODES). To test this , i have create the same folder structure in the postgresql server's machine and kept the errcodes.txt file in there. Then the COPY statement worked well. It looks very tough constraint for me with COPY statement.
Is there any setting needed to avoid this? or it is the behavior of COPY statement? I didn't find any information on PostgreSQL documents.
here's the standard solution:
COPY foo (i, j, k) FROM stdin;
1<TAB>2<TAB>3
\.
The data must be properly escaped and tab-separated.
Actually, it is in the docs, even in grammar definition you have STDIN... See: http://www.postgresql.org/docs/9.1/static/sql-copy.html
If you're using some programming language with COPY support, you will have pg_putcopy or similar function. So you don't have to worry about escaping and concatenation.
Hints how to do this manually in Python -> Recreating Postgres COPY directly in Python?
The Perl way -> http://search.cpan.org/dist/DBD-Pg/Pg.pm#COPY_support
Hope this helps.
From the documentation
Quote:
COPY with a file name instructs the PostgreSQL server to directly read from or write to a file. The file must be accessible to the server and the name must be specified from the viewpoint of the server. When STDIN or STDOUT is specified, data is transmitted via the connection between the client and the server.
If you want to copy from a local machine file to a server use \copy command.
I need to export the resulting data from a query in PostgreSQL to Excel/CSV.
I use PostgreSQL 8.2.11.
SQL error:
ERROR: relative path not allowed for COPY to file
In statement:
COPY (select distinct(m_price) from m_product)TO '"c:\auto_new.txt"';
Example with Unix-style file name:
COPY (SELECT * FROM tbl) TO '/var/lib/postgres/myfile1.csv' format csv;
Read the manual about COPY (link to version 8.2).
You have to use an absolute path for the target file. Be sure to double quote file names with spaces. Example for MS Windows:
COPY (SELECT * FROM tbl)
TO E'"C:\\Documents and Settings\\Tech\Desktop\\myfile1.csv"' format csv;
In PostgreSQL 8.2, with standard_conforming_strings = off per default, you need to double backslashes, because \ is a special character and interpreted by PostgreSQL. Works in any version. It's all in the fine manual:
filename
 The absolute path name of the input or output file. Windows users might need to use an E'' string and double backslashes used as path separators.
Or the modern syntax with standard_conforming_strings = on (default since Postgres 9.1):
COPY tbl -- short for (SELECT * FROM tbl)
TO '"C:\Documents and Settings\Tech\Desktop\myfile1.csv"' (format csv);
Or you can also use forward slashes for filenames under Windows.
An alternative is to use the meta-command \copy of the default terminal client psql.
You can also use a GUI like pgadmin and copy / paste from the result grid to Excel for small queries.
Closely related answer:
Copy results from a PostgreSQL view in one DB to a table in another
Similar solution for MySQL:
Exporting MYSQL data into Excel/CSV via php
In PostgreSQL 9.4 to create to file CSV with the header in Ubuntu:
COPY (SELECT * FROM tbl) TO '/home/user/Desktop/result_sql.csv' WITH CSV HEADER;
Note: The folder must be writable.
This worked for me:
COPY (SELECT * FROM table)
TO E'C:\\Program Files (x86)\\PostgreSQL\\8.4\\data\\try.csv';
In my case the problem was with the writing permission to a special folder (though I work as administrator), after changing the path to the original data folder under PostgreSQL I had success.
Several GUI tools like Squirrel, SQL Workbench/J, AnySQL, ExecuteQuery can export to Excel files.
Most of those tools are listed in the PostgreSQL wiki:
http://wiki.postgresql.org/wiki/Community_Guide_to_PostgreSQL_GUI_Tools
If you have error like "ERROR: could not open server file "/file": Permission denied" you can fix it that:
Ran through the same problem, and this is the solution I found:
Create a new folder (for instance, tmp) under /home
$ cd /home
make postgres the owner of that folder
$ chown -R postgres:postgres tmp
copy in tmp the files you want to write into the database, and make sure they also are owned by postgres.
That's it. You should be in business after that.
The correct script for postgres (Ubuntu) is:
COPY (SELECT * FROM tbl) TO '/var/lib/postgres/myfile1.csv';